Infiniti FX35 / FX45. Manual - part 382

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

EC-289

< SERVICE INFORMATION >

[VQ35DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)

Diagnosis Procedure

INFOID:0000000001326108

1.

CHECK EXHAUST GAS LEAK

1.

Start engine and run it at idle.

2.

Listen for an exhaust gas leak before three way catalyst 1.

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace.

2.

CHECK FOR INTAKE AIR LEAK

TER-

MI-

NAL 

NO.

WIRE 

COLOR

ITEM

CONDITION

DATA (DC Voltage)

24

L

A/F sensor 1 heater
 (bank 2)

[Engine is running]
• Warm-up condition
• Idle speed

Approximately 5V

40
41
42

LG
B
P

Fuel injector No. 6
Fuel injector No. 4 
Fuel injector No. 2

[Engine is running]
• Warm-up condition
• Idle speed

NOTE:
The pulse cycle changes depending on rpm 
at idle

BATTERY VOLTAGE

(11 - 14V)

[Engine is running]
• Warm-up condition
• Engine speed: 2,000 rpm

BATTERY VOLTAGE

(11 - 14V)

57

G

A/F sensor 1 (bank 2)

[Engine is running]
• Warm-up condition
• Idle speed

Approximately 2.6V

58

Y

Approximately 2.3V

76

P

Approximately 3.1V

77

BR

Approximately 2.3V

PBIB1584E

SEC984C

SEC985C

PBIB1922E

EC-290

< SERVICE INFORMATION >

[VQ35DE]

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

Listen for an intake air leak after the mass air flow sensor.

OK or NG

OK

>> GO TO 3.

NG

>>  Repair or replace.

3.

CHECK AIR FUEL RATIO (A/F) SENSOR 1 INPUT SIGNAL CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect corresponding A/F sensor 1 harness connector.

3.

Disconnect ECM harness connector.

4.

Check harness continuity between the following terminals.
Refer to Wiring Diagram.

5.

Check harness continuity between the following terminals and ground.
Refer to Wiring Diagram.

6.

Also check harness for short to ground and short to power.

OK or NG

OK

>> GO TO 4.

NG

>> Repair open circuit or short to ground or short to power in harness or connectors.

4.

CHECK FUEL PRESSURE

1.

Release fuel pressure to zero. Refer to 

EC-87, "Fuel Pressure Check"

.

2.

Install fuel pressure gauge and check fuel pressure. Refer to 

EC-87, "Fuel Pressure Check"

.

Bank 1

A/F sensor 1 terminal

ECM terminal

1

16

2

75

5

35

6

56

Bank 2

1

76

2

77

5

57

6

58

Continuity should exist.

Bank 1

Bank 2

A/F sensor 1 terminal

ECM terminal

A/F sensor 1 terminal

ECM terminal

1

16

1

76

2

75

2

77

5

35

5

57

6

56

6

58

Continuity should not exist.

PBIB2190E

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

EC-291

< SERVICE INFORMATION >

[VQ35DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

OK or NG

OK

>> GO TO 6.

NG

>> GO TO 5.

5.

DETECT MALFUNCTIONING PART

Check the following.
• Fuel pump and circuit (Refer to 

EC-558

.)

• Fuel pressure regulator (Refer to 

EC-87, "Fuel Pressure Check"

.)

>> Repair or replace.

6.

CHECK MASS AIR FLOW SENSOR

 With CONSULT-III

1.

Install all removed parts.

2.

Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-III.

 With GST

1.

Install all removed parts.

2.

Check mass air flow sensor signal in Service $01 with GST.

OK or NG

OK (With CONSULT-III)>>GO TO 7.
OK (Without CONSULT-III)>>GO TO 8.
NG

>> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or

ground. Refer to 

EC-175

.

7.

CHECK FUNCTION OF FUEL INJECTOR

 With CONSULT-III

1.

Start engine.

2.

Perform “POWER BALANCE” in “ACTIVE TEST” mode with CONSULT-III.

3.

Make sure that each circuit produces a momentary engine speed drop.

OK or NG

OK

>> GO TO 10.

NG

>> Perform trouble diagnosis for FUEL INJECTOR, refer to 

EC-552

.

8.

CHECK FUNCTION OF FUEL INJECTOR-I

 Without CONSULT-III

1.

Stop engine.

2.

Disconnect harness connector F50, F251

3.

Turn ignition switch ON.

At idling: Approximately 350 kPa (3.57 kg/cm

2

, 51 psi)

2.0 - 6.0 g·m/sec:

at idling

7.0 - 20.0 g·m/sec:

at 2,500 rpm

2.0 - 6.0 g·m/sec:

at idling

7.0 - 20.0 g·m/sec:

at 2,500 rpm

PBIB2624E

EC-292

< SERVICE INFORMATION >

[VQ35DE]

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

4.

Check voltage between harness connector F50 terminal 5 and
ground.

5.

Turn ignition switch OFF.

6.

Disconnect ECM harness connector.

7.

Check harness continuity between harness connector F50 and
ECM as follows.
Refer to Wiring Diagram.

8.

Also check harness for short to ground and short to power.

OK or NG

OK

>> GO TO 9.

NG

>> Perform trouble diagnosis for FUEL INJECTOR, refer to 

EC-552

.

9.

CHECK FUNCTION OF FUEL INJECTOR-II

Provide battery voltage between harness connector F251 as follows
and then interrupt it. Listen to each fuel injector operating sound.

OK or NG

OK

>> GO TO 10.

NG

>> Perform trouble diagnosis for FUEL INJECTOR, refer to 

EC-552

.

10.

CHECK FUEL INJECTOR

1.

Remove fuel injector assembly. Refer to 

EM-45

.

Keep fuel hose and all fuel injectors connected to fuel injector gallery.

2.

Confirm that the engine is cooled down and there are no fire hazards near the vehicle.

3.

Reconnect all harness connectors disconnected.

4.

Disconnect all fuel injector harness connectors.

5.

Disconnect all ignition coil harness connectors.

6.

Prepare pans or saucers under each fuel injectors.

7.

Crank engine for about 3 seconds.
Make sure fuel does not drip from fuel injector.

Voltage: Battery voltage

Cylinder

Harness connector F50 

terminal

ECM terminal

1

6

23

2

4

42

3

2

22

4

3

41

5

1

21

6

7

40

Continuity should exist.

PBIB2323E

Cylinder

Harness connector F251 terminal

(+)

(–)

1

5

6

2

4

3

2

4

3

5

1

6

7

Operating sound should exist.

PBIB2497E